THERMAL POLLUTION, CAUSE AND EFFECT OF THERMAL POLLUTION

Thermal Pollution is defined as the addition of excess of undesirable heat to water that makes it harmful to man, animal or aquatic life or otherwise causes significant departures from the normal activities of aquatic communities in water.

SOURCES OF THERMAL POLLUTION :

1. Nuclear Power plants

Nuclear power plants including drainage from hospitals, research institutes, nuclear experiments and explosions, discharged a lot of utilized heat and traces of toxic radio nuclides into nearby water streams.

2. Coal - fired power plants

Some Thermal power plants utilize coal as fuel, while a few plants use nuclear fuel. Coal - fired power plants constitute the major source of thermal pollutants.

3. Industrial effluents

Industries like textile, paper and pulp as well as sugar also release heat in water but to a much lesser extent.

4. Domestic sewage

Domestic sewage is commonly discharged into rivers, lakes , canals or streams with or without waste treatment.

5. Hydroelectric Power.

Generation of Hydroelectric power, sometimes, results in negative thermal loading in water systems.

EFFECTS OF THERMAL POLLUTION :

1. Reduction in dissolved oxygen

Concentration in dissolved oxygen (DO) decreases with increase in temperature of water.

2. Increase in Toxicity

The rising temperature increases the toxicity of the poison present in water .

3. Interference with biological activities

Temperature is considered to be vital significance to physiology metabolism and biochemical process in controlling respiratory rates, digestion, excretion and over all development of aquatic organisms. The temperature changes totally disrupt the entire ecosystem.

4. Interference with reproduction

In fishes, several activities like nest building, spanning, hatching, migration and reproduction etc., depend on optimum temperature.

5. Direct mortality

Unutilized heat in water is responsible for direct mortality in aquatic organisms.

6. Food storage for fish

Change in temperature alters the seasonal variation in the type and abundance of lower organisms. The fish may lack the right food at right time.

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Mechinopedia For Mechanical Engineers

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